ArcelorMittal will idle its rolling mill at its Conshohocken facility in Pennsylvania. The temporary closure will result in a layoff of up to 200 employees.

The company cites lower demand levels in bridge building, ships, tanks cars and military equipment, plus continued pressure from imported material, as the reason for the idling.

The mill will continue to operate its heat treat, finishing and inspection facilities. The site is used to finish steel rolled at its Coatesville, Pa., and Burns Harbor, Ind., operations. The company says customers will see limited impact from the decision.

The United Steelworkers responded to the announcement by writing letters to Commerce Secretary Wilbur Ross and Secretary of Defense James Mattis, asking the Trump Administration to complete its Section 232 investigation into the national security impact of steel imports.

"The idling of this steel facility and layoff of more than 200 highly skilled steel workers is another direct blow to our national security," says USW International President Leo Gerard. "Our soldiers deployed in harm's way depend on products made in this facility in building Mine-Resistant Ambush-Protected vehicles, Bradley land systems and all Navy Seapower systems. This steel closure is on the administration's watch. At what point will they conclude their investigation and act?"

"Originally we were told that the steel investigation would be done by June," says USW International Vice President Thomas Conway. "Now, press reports indicate the work is essentially done, but the White House wants to wait until Congress finishes tax reform. The White House needs to get its priorities straight."